Systems and methods for intercepting data relating to storage volume access

ABSTRACT

A target world wide port name of a target port of a storage system is identified, by a device located in a path between a switch port of a switch and the target port of the storage system. A first port of the device is registered with the switch based on the target world wide port name, in a first registration procedure. Registration information relating to an initiator port of a server that is associated with the target port is received, in a second registration procedure. An initiator world wide port name of the initiator port of the server is determined, based on the registration information. A storage volume in the storage system that is associated with the initiator port is identified, based on the initiator world wide port name of the initiator port.

This application is a continuation of U.S. patent application Ser. No. 13/336,257, filed Dec. 23, 2011, which is incorporated herein by reference.

TECHNICAL FIELD

This specification relates generally to systems and methods for storing and managing data, and more particularly to systems and methods for providing data management services with respect to data maintained in a storage system.

BACKGROUND

The storage of electronic data, and more generally, the management of electronic data, has become increasingly important. With the growth of the Internet, and of cloud computing in particular, the need for data storage capacity, and for methods of efficiently managing stored data, continue to increase. Many different types of storage devices and storage systems are currently used to store data, including disk drives, tape drives, optical disks, redundant arrays of independent disks (RAIDs), Fibre channel-based storage area networks (SANs), etc.

In many enterprise-level storage systems, it is useful to add data management services to the existing storage system in order to perform one or more desired tasks. For example, it may be useful in some storage systems to add functionality to copy data, to perform a snapshot of a data image, to back up data, to replicate data, to perform data migration from one storage device or system to another, etc. It is typically desirable to install any additional functionality for performing such services without causing any interruption to the storage system's operations.

SUMMARY

In accordance with an embodiment, a method of providing data management services is provided. A target world wide port name of a target port of a storage system is identified, by a device located in a path between a switch port of a switch and the target port of the storage system. A first port of the device is registered with the switch based on the target world wide port name, in a first registration procedure. Registration information relating to an initiator port of a server that is associated with the target port is received, in a second registration procedure. An initiator world wide port name of the initiator port of the server is determined, based on the registration information. A storage volume in the storage system that is associated with the initiator port is identified, based on the initiator world wide port name of the initiator port.

In one embodiment, the target world wide port name is assigned to the first port of the device.

In another embodiment, the second registration procedure may comprise registration by the initiator port with the device via the first port. In one embodiment, a switch port identifier associated with an initiator port of a server that is zoned to the target port is received, in the second registration procedure.

In another embodiment, a Simple Name Server table that identifies, for each of one or more switch ports of the switch, a corresponding world wide port name, is accessed.

In one embodiment, a REPORT LUN command including the initiator world wide port name is transmitted to the storage system. Information identifying the storage volume to which the initiator world wide port name has access is received from the storage system, in response to the REPORT LUN command.

In another embodiment, a SCSI inquiry relating to the storage volume to which the initiator world wide port name has access is transmitted to the storage system. Information indicating a global unique identifier of the storage volume is received, in response to the SCSI inquiry. A determination of whether two storage volumes associated with the initiator world wide port name are identical is made, based on the global unique identifier.

In one embodiment, the switch is a Fibre channel switch.

In accordance with another embodiment, a device located in a network between a switch port of a switch and a target port of a storage system is provided. The device comprises a first port and a processor. The processor is configured to identify a target world wide port name of a target port of the storage system, and to register, in a first registration procedure, the first port with the switch based on the target world wide port name. The processor is further configured to receive, in a second registration procedure, registration information relating to an initiator port of a server that is associated with the target port, to determine an initiator world wide port name of the initiator port of the server, based on the registration information, and to identify one or more storage volumes in the storage system that is associated with the initiator port, based on the initiator world wide port name of the initiator port.

In another embodiment, a method of providing a data management service is provided. An identifier of an initiator port of a host entity connected to a switch is determined, by a device located in a path between a switch port of the switch and a target port of a storage system. A storage volume in the storage system to which the initiator port has access is identified, based on the identifier. A data management service is provided with respect to the identified storage volume. The identifier may be a world wide port name.

In one embodiment, the data management service may include one of: copying data, performing a snapshot of a data image, replicating data, performing a data migration service, monitoring I/O commands sent to and from a selected volume maintained in a storage system, generating statistics relating to I/O commands, and calling a predetermined function to perform a specified action based on a detection of a predetermined condition.

In another embodiment, a device located in a network, in a path between a switch port of a switch and a target port of a storage system, is provided. The device comprises a first port connected to the switch, a second port connected to the storage system, and at least one processor. The processor is configured to determine an identifier of an initiator port of a host entity connected to the switch, to identify a storage volume in the storage system to which the initiator port has access, based on the identifier, and to provide a data management service with respect to the identified storage volume.

In another embodiment, an apparatus is provided. The apparatus includes means for identifying a target world wide port name of a target port of a storage device, means for registering, in a first registration procedure, a first port with a switch based on the target world wide port name, and means for receiving, in a second registration procedure, registration information relating to an initiator port of a server that is associated with the target port. The apparatus also includes means for determining an initiator world wide port name of the initiator port of the server, based on the registration information, and means for identifying a storage volume in the storage system that is associated with the initiator port, based on the initiator world wide port name of the initiator port.

In another embodiment, a system for providing data storage services and data management services is provided. The system comprises a storage system that comprises a storage adapted to store one or more storage volumes, and at least one target port adapted to transmit and receive I/O commands relating to the one or more storage volumes. The system also comprises a server comprising at least one initiator port adapted to transmit and receive I/O commands relating to the one or more storage volumes. The system also comprises a switch that comprises a plurality of switch ports adapted to transmit and receive I/O commands, and a switch manager adapted to direct a selected I/O command from a first selected switch port to a second selected switch port. The system further comprises an appliance, located in a path between a switch port of the switch and a target port of the storage system, wherein the appliance is adapted to determine an identifier of a selected initiator port of the server, identify a storage volume in the storage system to which the selected initiator port has access, based on the identifier, and provide a data management service with respect to the identified storage volume.

These and other advantages of the present disclosure will be apparent to those of ordinary skill in the art by reference to the following Detailed Description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a communication system that may be used to provide data storage services and data management services in accordance with an embodiment;

FIG. 2 shows components of a Fibre Channel-based storage area network (SAN) in accordance with an embodiment;

FIG. 3 shows functional components of a server in accordance with an embodiment;

FIG. 4 shows functional components of a storage system in accordance with an embodiment;

FIG. 5 shows functional components of a Fibre channel switch in accordance with an embodiment;

FIG. 6 shows an example of a Simple Name Server table in accordance with an embodiment;

FIG. 7 shows an example of a zoning configuration that may be established within a Fibre channel switch in accordance with an embodiment;

FIG. 8 shows functional components of an interceptor appliance in accordance with an embodiment;

FIG. 9A shows the Fibre channel-based SAN of FIG. 2 after a link between the Fibre channel switch and the storage system has been removed, in accordance with an embodiment;

FIG. 9B shows the Fibre channel-based SAN of FIG. 2 after an interceptor appliance has been inserted between the Fibre channel switch and the storage system, in accordance with an embodiment;

FIG. 10 is a flowchart of a method for communicating with components of a network, in accordance with an embodiment;

FIG. 11 shows a communication system that may be used to provide data storage services and data management services in accordance with an embodiment;

FIG. 12 is a flowchart of a method of providing data management services in accordance with an embodiment; and

FIG. 13 shows an exemplary computer that may be used to implement certain embodiments of the invention.

DETAILED DESCRIPTION

In accordance with various embodiments, methods and systems for providing data storage services and data management services are provided. In one embodiment, an interceptor device is inserted in a network, in a path between a switch port of a switch and a target port of a storage system. In one embodiment, the interceptor device is inserted in a Storage Area Network (SAN). The interceptor device spoofs selected components of the storage area network to obtain information concerning storage configuration and data stored in the storage system. Specifically, a target world wide port name of the target port is identified by the device, and an upstream port of the device registers with the switch based on the target world wide port name, in a first registration procedure. Registration information identifying an initiator world wide port name of an initiator port of a host entity that is zoned to the target port is received, in a second registration procedure. Registration information may be received from one or more initiator ports. The initiator world wide port names of the initiator ports are determined based on the registration information. For each of the one or more initiator ports of the host entity, one or more storage volumes in the storage system associated with the respective initiator port are identified, based on the initiator world wide port name of the respective initiator port. In this manner, the interceptor device identifies one or more storage volumes to which the host entity has access.

After identifying the storage volumes that the host entity may access, the interceptor device may provide additional data management services with respect to data stored in the volumes. For example, the interceptor device may copy data, perform a snapshot of the data, back up the data, replicate the data, perform a data migration operation, etc.

FIG. 1 shows a communication system 100 that may be used to provide data storage and data management services in accordance with an embodiment. Communication system 100 includes a first network 105, one or more clients 160-A, 160-B, etc., and one or more servers 135-A, 135-B, etc. Communication system 100 also comprises a second network 115 and a storage system 180. While two clients 160 are shown in FIG. 1, in other embodiments communication system 100 may include more or fewer than two clients. Similarly, while two servers 135 are shown in FIG. 1, in other embodiments communication system 100 may include more or fewer than two servers.

For convenience, the term “client 160” is used herein to refer to any one of clients 160-A, 160-B, etc. Accordingly, any discussion herein referring to “client 160” is equally applicable to each of clients 160-A, 160-B, etc. Similarly, the term “server 135” is used herein to refer to any one of servers 135-A, 135-B, etc. Accordingly, any discussion herein referring to “server 135” is equally applicable to each of servers 135-A, 135-B, etc.

Storage system 180 stores data. For example, storage system 180 may store any type of data, including, without limitation, files, spreadsheets, images, audio files, source code files, etc. Storage system 180 may from time to time receive, from another device, a request to store specified data, and in response, store the specified data. For example, storage system 180 may store data received from a server 135. Storage system 180 may also from time to time receive, from another device, a request to access stored data and, in response, provide the requested data to the requesting device, or provide access to the requested data. Storage system 180 may verify that the requesting device is authorized to access the requested data prior to providing access to the data. Storage system 180 is connected to network 115.

Network 115 may comprise one or more of a number of different types of networks, such as, for example, a Fibre Channel-based storage area network (SAN), an iSCSI-based network, a local area network (LAN), a wide area network (WAN), or a wireless network. Other networks may be used.

Server 135 from time to time receives from a client 160 a request for stored data, communicates with storage system 180 to retrieve the requested data, and provides the requested data to the requesting client. Server 135 is connected to network 115 and communicates with storage system 180 via network 115. Server 135 is also connected to network 105 and communicates with clients 160 via network 105. For example, server 135 may be a personal computer, a workstation, a mainframe computer, a server computer, a workstation, etc. In some embodiments, a server, or a cluster of two or more servers, may be defined as a “host entity.”

In the exemplary embodiment of FIG. 1, network 105 may include one or more of a number of different types of networks, such as, for example, an intranet, a local area network (LAN), a wide area network (WAN), or a wireless network. Other networks may be used. Alternatively, network 105 may include a combination of different types of networks.

Client 160 may be any computer or other device capable of communicating via network 105. For example, client 160 may be, without limitation, a personal computer, a laptop computer, a tablet device, a server computer, a mainframe computer, a workstation, a wireless device such as a cellular telephone, a personal digital assistant, etc. Client 160 from time to time transmits a request for data to a server 135. For example, client 160 may transmit to server 135 a request for stored data when a user of client 160 requests access to a web page, to a stored file, to a stored email, to stored data relating to an account, etc.

In one embodiment, server 135 may comprise a web server that maintains a website and provides access to one or more web pages associated with the website. More particularly, server 135 may provide to clients 160 one or more cloud-based services, including a cloud-based storage service that allows a client 160 to store data remotely, and transparently, via the Internet, and to access the stored data via the Internet.

In other embodiments, server 135 may provide other types of services. For example, server 135 may comprise a file server that provides access to stored files, an email server that provides access to stored emails, etc.

In an illustrative embodiment, network 115 is a Fibre Channel-based storage area network (SAN). FIG. 2 shows components of Fibre channel-based storage area network (SAN) 115 in accordance with an embodiment. Fibre channel-based storage area network (SAN) 115 comprises one or more servers, including server 135-A and server 135-B, storage system 180, and a Fibre channel switch 225. Server 135-A is connected to Fibre channel (FC) switch 225 by links 271 and 272. Server 135-B is connected to FC switch 225 by links 273 and 274. FC switch 225 is connected to storage system 180 by links 281 and 282. In other embodiments, Fibre channel-based SAN 115 may have any type of topology, including, without limitation, a point-to-point topology, an arbitrated loop topology, a switched fabric topology, or other topology.

Certain devices within Fibre channel-based SAN 115 include one or more ports; a port is an entity that actively communicates via network 115. Ports located on servers 135 are sometimes referred to herein as initiator ports. Ports located on storage system 180 are sometimes referred to herein as target ports. Ports located on FC switch 225 are sometimes referred to herein as switch ports. In the illustrative embodiment of FIG. 2, server 135-A includes initiator ports I-1 and I-2, and server 135-B includes initiator ports I-3 and I-4. Storage system 180 includes target ports T-1 and T-2. FC switch 225 includes switch ports P-1, P-2, P-3, P-4, P-5, and P-6. Servers 135, storage system 180, and FC switch 225 may comprise more or fewer ports than those shown in FIG. 2.

Data is transmitted within Fibre channel-based SAN 115 via links. In the illustrative embodiment, link 271 connects initiator port I-1 (of server 135-A) to port P-1 of FC switch 225. Link 272 connects initiator port I-2 (of server 135-A) to port P-2 of FC switch 225. Link 273 connects initiator port I-3 (of server 135-B) to port P-3 of FC switch 225. Link 274 connects initiator port I-4 of server 135-B to port P-4 of FC switch 225. Link 281 connects port P-5 of FC switch 225 to target port T-1 of storage system 180. Link 282 connects port P-6 of FC switch 225 to target port T-2 of storage system 180.

In an embodiment, communications among components of Fibre-Channel-based SAN 115 are conducted in accordance with Fibre Channel Protocol (FCP). For example, servers 135, FC switch 225 and storage system 180 may transmit SCSI commands via network 115.

FIG. 3 shows functional components of a server 135 in accordance with an embodiment. For exemplary purposes, FIG. 3 shows components of server 135-A; however, FIG. 3 and the discussion below is equally applicable to any server in communication system 100. Server 135-A includes a service manager 325, a memory 375, and initiator ports I-1 and I-2. Server 135-A may include more or fewer than two initiator ports.

Service manager 325 controls the activities of various components within server 135-A. Service manager 325 is a functional process that may be implemented by software, hardware, or a combination of software and hardware. Memory 375 is used by various components of server 135-A to store data. In the illustrative embodiment of FIG. 3, initiator ports I-1 and I-2 are implemented in a host bus adapter 362 located in server 135-A. Server 135-A may include multiple host bus adapters. In other embodiments, initiator ports I-1 and I-2 may be implemented in a different component of server 135-A. Server 135-A may include components not shown in FIG. 3.

FIG. 4 shows functional components of storage system 180 in accordance with an embodiment. Storage system 180 comprises a storage manager 410, a memory 475, and a storage 468. Storage manager 410 controls the operations of various components of storage system 180. Storage manager 410 may comprise functionality to store data using one or more of a variety of data storage techniques. For example, storage manager 410 may store data using a virtualization method, using various RAID configurations, etc. Storage manager 410 is a functional process that may be implemented by software, hardware, or a combination of software and hardware. Memory 475 may be used by various components of storage system 180 to store data. Storage system 180 also comprises target ports T-1 and T-2. In one embodiment, target ports T-1 and T-2 may be implemented in one or more host bus adapters. In one embodiment, storage manager 410 and one or more target ports may be implemented as a subsystem referred to as a storage controller. Storage system 180 may include components not shown in FIG. 4.

Storage 468 comprises one or more storage devices (not shown) capable of storing data. Storage 468 may comprise one or more block-level storage devices, one or more file-level storage devices, and/or other types of storage devices. For example, storage 468 may comprise, without limitation, one or more disk drives, optical disks, tape drives, etc. Storage 468 may comprise a redundant array of independent disks (RAID) or multiple RAIDS. Storage 468 may include local and/or distributed storage. Other types of storage devices may be used.

Data stored in storage system 180 may be organized into logical unit numbers (LUNs), also referred to as volumes. In the illustrative embodiment of FIG. 4, storage 468 includes a plurality of volumes, including volumes 491 and 492. A LUN, or volume, is a logical unit and therefore may comprise data distributed across multiple storage devices.

FIG. 5 shows functional components of FC switch 225 in accordance with an embodiment. FC switch 225 comprises a switch manager 525 and a memory 575. Switch manager 525 controls the activities of various components within FC switch 225. Switch manager 525 is a functional process that may be implemented by software, hardware, or a combination of software and hardware. Memory 575 is used by various components of FC switch 225 to store control data. FC switch 225 also comprises switch ports P-1, P-2, P-3, P-4, P-5, and P-6. In one embodiment, ports P-1, P-2, P-3, P-4, P-5, and P-6 may be implemented using one or more host bus adapters. FC switch 225 may include components not shown in FIG. 5.

From time to time switch manager 525 may direct an I/O command received at a first switch port of FC 225 to a second switch port of FC switch 225.

When a port on a device within Fibre channel-based SAN 115 is connected to FC switch 225, the port logs in, or registers, with FC switch 225, in a known registration procedure, or in a log-in procedure. Each Fibre channel port is assigned a unique identifier referred to as a world wide port name (WWPN) by the manufacturer of the device. Each WWPN is a unique sixty-four bit number. Accordingly, each initiator ports I-1, I-2, I-3, and I-4 has a respective WWPN. Each of ports P-1 through P-6 on FC switch 225 also has a respective WWPN. Each of target ports T-1 and T-2 of storage system 180 has a respective WWPN.

For convenience only, a world wide port name of an initiator port is referred to herein as an initiator world wide port name, and a world wide port name of a target port is referred to herein as a target world wide port name. However, as discussed above, each world wide port name (regardless of whether it is associated with an initiator port or a target port) is a unique sixty-four bit number. The terms initiator world wide port name and target world wide port name are used herein for convenience only; these terms do not reflect different “types” of world wide port names, and do not reflect any characteristic of a world wide port name itself that distinguishes a world wide port name associated with an initiator port from a world wide port name associated with a target port.

FC switch 225 maintains a Simple Name Server table to store information concerning various ports within Fibre channel-based SAN 115. FIG. 6 shows an example of a Simple Name Server table in accordance with an embodiment. Simple Name Server table 650 comprises a column 625 that stores a world wide port name of an initiator port or target port, and a column 629 that stores an identifier of a port of FC switch 225 to which the initiator or target port is connected. Referring to record 602, a first world wide port name, WWPN-1, which is assigned to initiator port I-1, is connected to port P-1 on FC switch 225. Record 604 indicates that WWPN-2 (assigned to initiator port I-2) is connected to port P-2 on FC switch 225. Record 606 indicates that WWPN-3 (assigned to initiator port I-3) is connected to port P-3 on FC switch 225. Record 614 indicates that WWPN-5 (assigned to target port T-1) is connected to port P-5 on FC switch 225.

Simple Name Server table 650 is stored in memory 575 of FC switch 225, as shown in FIG. 5. Server 135 and storage system 180 may from time to time be given access Simple Name Server table 650.

When an initiator port of a server 135, or a target port of storage system 180, is connected to a port on FC switch 225, the initiator or target port transmits a registration request, also referred to as a Fibre channel log-in request, to FC switch 225. In response, Simple Name Server table 650 is updated to record the WWPN of the requesting port and the corresponding port on FC switch 225. When an initiator or target port is disconnected from FC switch 225, Simple Name Server table 650 is updated to reflect the change.

I/O Commands

From time to time, a server 135 may generate and transmit to storage system 180 (via FC switch 225) an input/output (I/O) command requesting that storage system 180 store data in a specified storage volume. An I/O command that relates to a particular storage volume, originates from a particular initiator port on server 135, and is intended for a desired target port of storage system 180 may include, among other data, (1) an identifier of the port on switch 225 that corresponds to (i.e., that is connected to) the originating initiator port of server 135; (2) an identifier of a port of switch 225 that corresponds to (i.e., that is connected to) the desired target port of storage system 180; and (3) an identifier of the particular volume to which the I/O command is related.

LUN Masking

It is sometimes desirable to limit or restrict access to a particular storage volume to a single server or to a cluster of one or more servers defined as a single host entity. Accordingly, in accordance with an embodiment, a particular volume maintained in storage system 180 may be assigned to all ports of a selected server (and to no other ports on any other server). In another embodiment, access to a particular storage volume may be limited to a particular host entity (which may include multiple servers). Accordingly, the storage volume may be assigned to all ports of each server associated with the host entity. Specifically, volumes are assigned to one or more WWPNs associated with respective initiator ports. Assignment information indicating assignments of storage volumes to various initiator WWPNs is maintained by storage system 180. Storage system 180 grants access to the storage volume in accordance with the assignments, using a method referred to as “LUN masking.” Examples of techniques for performing LUN masking are described below.

In the illustrative embodiment, access to volume-1 (491), shown in FIG. 4, is granted to server 135-A (and not to server 135-B or to any other server). Accordingly, volume-1 (491) is assigned to the WWPN of initiator port I-1 and to the WWPN of initiator port I-2 of server 135-A.

Accordingly, in an example of a LUN masking technique, when storage manager 410 of storage system 180 receives an I/O command specifying volume-1 (491), storage manager 410 retrieves from the I/O command information that may be used to determine the WWPN of the originating initiator port. If the storage volume is assigned to that particular WWPN, storage manager 410 provides access to the volume. For example, if an I/O command specifies volume-1 and originated at initiator port I-1, storage system 180 verifies that volume-1 is assigned to the WWPN of initiator port I-1, and grants access to volume-1. If the volume is not assigned to the originating WWPN, storage manager 410 rejects the I/O command, denying access to the volume.

Zoning

Using a method referred to as zoning, internal paths between ports of FC switch 225 may be configured in accordance with one or more predetermined policies. For example, FC switch 225 may be configured to ensure that a first port of switch 225 is linked, or zoned, only to a specified second port of switch 225. Alternatively, FC switch 225 may be configured to ensure that a first specified port of FC switch 225 is zoned to two or more ports of FC switch 225. FIG. 7 shows an example of a zoning configuration that may be established within FC switch 225 in accordance with an embodiment. In the illustrative embodiment of FIG. 7, port P-1 is zoned to port P-5 via internal path 771, port P-2 is zoned to port P-5 via internal path 772 and to port P-6 via internal path 773, port P-3 is zoned to port P-6 via internal path 774, and port P-4 is zoned to port P-6 via internal path 775. Other zoning arrangements different from that shown in FIG. 7 may be used. In one accordance with one zoning method known as hard-zoning, zoning is established based on switch ports.

In a zoning method referred to as soft zoning, a zoning configuration can be established within FC switch 225 by defining relationships among initiator ports of server 135 and target ports of storage system 180. An initiator port of a server 135 may be zoned to a target port of storage system 180 notwithstanding the physical connections between various ports. In the illustrative embodiment (referring to FIGS. 2 and 7), initiator port I-1 of server 135-A can be zoned only to target port T-1 of storage system 180, specifically from initiator port I-1 to port P-1 of FC switch 225 via link 271, then internally to port P-5 of FC switch 225 via internal path 771, then to target port T-1 of storage system 180. Therefore, initiator port I-1 of server 135-A can transmit data to, and receive data from, only target port T-1 of storage system 180. Note that while in this example initiator port I-1 is connected to ports P-1 and P-5 of FC switch 225, initiator port I-1 could be connected to any other switch ports, using a soft zoning method based on WWPNs of various ports instead of physical ports.

In the illustrative embodiment, initiator port I-2 of server 135-A is zoned to two target ports of storage system 180. Specifically, initiator port I-2 is zoned to target port T-1 through a first path from initiator port I-2 to port P-2 of FC switch 225 via link 272, then internally to port P-5 of FC switch 225 via internal path 772, then to target port T-1 of storage system 180 via link 281. Initiator port I-2 is also zoned to target port T-2 of storage system 180 through a second path from initiator port I-2 to port P-2 of FC switch 225 via link 272, then internally to port P-6 of FC switch 225 via internal path 773, then to target port T-2 of storage system 180 via link 282. Therefore, initiator port I-2 of server 135-A can transmit data to, and receive data from, both target ports T-1 and T-2 of storage system 180. As discussed above, the zoning configuration can be changed based on WWPNs of various ports, using a soft zoning method, notwithstanding the physical connections between various ports.

Multipath Functionality

In an embodiment, server 135-A includes functionality to determine relationships between paths defined by a particular zoning configuration within FC switch 225, as well as LUN masking within storage system 180, and various volumes maintained in storage system 180. For example, referring to FIG. 3, service manager 325 of server 135-A may include multipath functionality. Alternatively, such functionality may be implemented by a separate software application residing on server 135-A. Such a software application is sometimes referred to as multipath software application.

In the illustrative embodiment, service manager 325 uses multipath functionality to examine all available paths between server 135-A and storage system 180 (in view of any internal zoning established within FC switch 225 and LUN masking established in storage system 180) and to identify each storage volume that may be accessed via each respective path. Thus, service manager 325 determines that initiator port I-1 is zoned to only one target port, T-1, of storage system 180. Service manager 325 further determines that this particular path allows access to one particular storage volume. Service manager 325 additionally determines that initiator port I-2 is zoned to two ports, T-1 and T-2, of storage system 180. Service manager 325 also determines that each of these paths allows access to one storage volume. This determination may be performed based on the world wide port names associated with the respective initiator ports of server 135, and based on LUN masking.

The information obtained by service manager 325 concerning which volumes are accessible to each respective initiator port may be ambiguous and fail to specify how many unique volumes are accessible to the various initiator ports.

Service manager 325 uses multipath functionality to reconcile the accessible storage volumes to determine how many unique storage volumes are in fact accessible from initiator ports I-1 and I-2. In the illustrative embodiment, service manager 325 examines each of the three defined paths between server 135-A and storage system 180, and determine that all three paths enable access to the same volume-1 (491), rather than to three different storage volumes.

Using an additional aspect of multipath functionality, service manager 325 reroutes traffic between server 135-A and storage system 180, from a first path to a second path, as needed, to ensure continual communication concerning a particular storage volume. For example, if service manager 325 detects an interruption in the flow of data on link 281 between FC switch 225 and storage system 180, interrupting communications relating to volume-1 (491), service manager 325 may redirect all communications relating to volume-1 (491) to another available path that enables access to volume-1 (491), such as a path originating from initiator port I-2 that utilizes link 282.

Interceptor Appliance

In many enterprise-level storage systems, it is useful to add data management services to the existing storage system. For example, it is often useful to add functionality to copy data, perform a snapshot of a data image, back up data, replicate data, perform data migration from one storage device or system to another, etc. It is preferable to add such functionality without causing any interruption to the storage system's operations.

One solution is to add functionality to the server or host entity. For example, a specialized driver (e.g., a software application) may be installed in a server to intercept I/O commands transmitted to a storage system. However, this solution is disadvantageous for several reasons. Installing software on a server creates the risk that any problem with the installed application may slow down or even cause the server to crash. Another problem with this approach is that different software must be created suitable to the operating system platforms used on various servers. Creating different drivers for use on different servers is inefficient and undesirable.

The inventor has identified a solution that comprises systems and methods for inserting in the data path between a Fibre channel switch and a storage system a device, or appliance, having functionality to intercept all I/O commands transparently and to provide data management services with respect to data stored in the storage system. The inventor has further identified a solution comprising systems and methods for perform the insertion of such a device or appliance transparently, without interrupting the operation of the storage system, and without requiring any system downtime.

Accordingly, in one embodiment, an interceptor appliance is inserted between a selected port of FC switch 225 and a selected target port of storage system 180. The interceptor appliance determines the WWPN of the selected target port of storage system 180, determines the WWPN of each initiator port of a server, or host entity, that is zoned to the selected target port of storage system 180, and identifies all storage volumes in the storage system that are assigned to each respective WWPN of the server or host entity.

FIG. 8 shows functional components of an interceptor appliance 890 in accordance with an embodiment. Interceptor appliance 890 comprises an interceptor process 810, a memory 815, and a data management service 848. Interceptor process 810 controls the operations of various components of interceptor appliance 890. Interceptor process 810 is a functional process that may be implemented by software, hardware, or a combination of software and hardware. Memory 815 is used by various components of interceptor appliance 890 to store data. Interceptor appliance 890 also comprises interceptor ports 846 and 847. Interceptor ports 846 and 847 may be implemented using one or more host bus adapters.

In one embodiment, interceptor appliance 890 comprises a computer. Other types of processing devices may be used.

Interceptor appliance 890 may be inserted between a selected port of FC switch 225 and a target port of storage system 180 using any one of a variety of methods. For example, in an illustrative embodiment, link 281 between port P-5 of FC switch 225 and target port T-1 of storage system 180 is removed, as shown in FIG. 9A.

Multipath functionality in server 135 ensures that removal of link 281 does not interrupt the flow of data with respect to any volume maintained in storage system 180. For example, service manager 325 of server 135 may detect the removal of link 281 and determine that initiator port I-1 can no longer communicate with storage system 180. Service manager 325 may use multipath functionality to determine that any I/O command relating to volume-1 may be redirected from initiator port I-1 (which can no longer communicate with storage system 180 due to removal of link 281) to initiator port I-2, which also has access to volume-1 and can communicate with storage system 180 through another available path.

In the illustrative embodiment, interceptor appliance 890 is inserted in the following manner. Referring to FIG. 9B, interceptor port 846 of interceptor appliance 890 is connected to port P-5 of FC switch 225 by a link 981, and interceptor port 847 is connected to target port T-1 of storage system 180 by a link 982.

Interceptor appliance 890 now communicates with components of Fibre channel-based SAN 115 in order to obtain information concerning data stored in storage system 180. FIG. 10 is a flowchart of a method for communicating with a components of a network, in accordance with an embodiment. At step 1010, a target world wide port name of a target port of a storage system is identified, by a device located in a path between a switch port of a switch and the target port of the storage system. In the illustrative embodiment, when target port T-1 of storage system 180 is connected to interceptor port 847 of interceptor appliance 890, target port T-1 attempts to register with interceptor appliance 890. Accordingly, target port T-1 transmits to interceptor appliance 890 a request to register, or to complete a Fibre channel log-in. The request contains the WWPN of target port T-1. Interceptor appliance 890 receives the request and retrieves the WWPN of target port T-1.

At step 1020, an upstream port of the device is registered with the switch based on the target world wide port name, in a first registration procedure, or Fibre channel log-in procedure. In the illustrative embodiment, (upstream) interceptor port 846 uses the WWPN of target port T-1 to spoof target port T-1 and obtain information from FC switch 225. Specifically, interceptor appliance 890 transmits from (upstream) interceptor port 846 a request to register with FC switch 225. The request to register includes the target world wide port name of target port T-1 (and may additionally include a second world wide port name unique to interceptor port 846). FC switch 225 receives the request to register and registers interceptor port 846 based on the target world wide port name of target port T-1. FC switch 225 may additionally register interceptor port 846 based on the second world wide port name unique to interceptor port 846.

At step 1030, registration information relating to an initiator port of a server that is associated with the target port is received, in a second registration procedure. In the illustrative embodiment, the registration information received from an initiator port includes information identifying the initiator port's world wide port name. The registration information received from an initiator port may also include information specifying a switch port to which the initiator port is connected.

Accordingly, when interceptor port 846 registers with FC switch 225 using the world wide port name of target port T-1, all initiator ports of any server 135 (or host entity) that are zoned to target port T-1 register with interceptor port 846, in a second registration procedure.

During the second registration procedure, each initiator port transmits registration information identifying its respective world wide port name. Thus, each of initiator ports I-1 and I-2 (which are zoned to target port T-1) registers with interceptor port 846 and provides to interceptor port 846 information specifying its world wide port name. Specifically, initiator port I-1 provides in the registration information its world wide port name (WWPN-1) and initiator port I-2 provides its world wide port name (WWPN-2). Initiator port I-1 may also include in the registration information a switch port identifier identifying switch port P-1, to which it is connected. Initiator port I-2 may also include in the registration information a switch port identifier identifying switch port P-2, to which it is connected.

At step 1040, an initiator world wide port name of the initiator port of the server (or host entity) is determined, based on the registration information. Thus, interceptor appliance 890 obtains the world wide port name of each initiator port of server 135-A from the registration information that was received. Specifically, interceptor process 810 of interceptor appliance 890 determines that WWPN-1 is the world wide port name of initiator port I-1 and that WWPN-2 is the world wide port name of initiator port I-2. In this manner, interceptor appliance 890 determines the initiator world wide port name of each initiator port of server 135-A that is zoned to target port T-1 of storage system 180.

In an alternative embodiment, the registration information received from an initiator port does not include the initiator port's world wide port name, but includes a switch port identifier identifying a switch port to which the initiator port is connected. For example, initiator port I-1 provides registration information indicating that it is connected to switch port P-1, and initiator port I-2 provides registration information indicating that it is connected to switch port P-2. Interceptor appliance 890 accordingly accesses and examines Simple Name Server table 650 and identifies, for each switch port identifier received, a corresponding initiator world wide port name. Specifically, interceptor process 810 of interceptor appliance 890 consults Simple Name Server table 650 and determines that WWPN-1 is associated with switch port identifier P-1 (and thus is linked to port P-1 of FC switch 225), and that WWPN-2 is associated with switch port identifier P-2 (and thus is linked to port P-2 of FC switch 225).

At step 1050, one or more storage volumes in the storage system that are associated with the initiator port are identified, based on the initiator world wide port name of the initiator port. In the illustrative embodiment, interceptor appliance 890 now spoofs each initiator port of server 135 to obtain information from storage system 180. Specifically, interceptor process 810 of interceptor appliance 890 uses a standard procedure to add the initiator world wide port names of the initiator ports that are zoned to target port T-1 to (downstream) interceptor port 847 of interceptor appliance 890. Thus interceptor process 810 adds WWPN-1 and WWPN-2 to interceptor port 847. After the initiator world wide port names are added to interceptor port 847, interceptor process 810 may obtain from storage system 180 information identifying one or more volumes to which each respective initiator world wide port name has access, in the manner described below.

For each initiator world wide port name now associated with port 847 of interceptor appliance 890, interceptor process 810 transmits to storage system 180 a command specifying the respective initiator WWPN and requesting information identifying the volumes to which the initiator WWPN has access. For example, interceptor process 810 may transmit a REPORT LUN command in accordance with SCSI protocols. Storage system 180 receives the command and, in response, transmits information indicating one or more volumes to which the specified initiator WWPN has access. Thus, in the illustrative embodiment, interceptor process 810 transmits to storage system 180 a REPORT LUN command specifying WWPN-1. In response, storage system 180 transmits to interceptor appliance 890 information indicating that WWPN-1 has access to volume-1 (491). Interceptor process 810 also transmits to storage system 180 a REPORT LUN command specifying WWPN-2. In response, storage system 180 informs interceptor appliance 890 that WWPN-2 has access to volume-1 (491).

As discussed above, in some embodiments the information received from storage system 180 concerning which volumes are accessible to each respective initiator world wide port name may be ambiguous and fail to specify how many unique volumes are accessible to the various initiator world wide port names. As a result, interceptor appliance 890 may interpret the information obtained from storage system 180 as indicating more storage volumes that actually exist. Therefore, interceptor appliance 890 may reconcile the information received from storage system 180 to determine if the identified storage volumes are unique, or if two or more of the identified storage volumes are identical and therefore redundant.

Accordingly, in one embodiment, interceptor process 810 transmits a command (such as a SCSI command referred to as an INQUIRY command) to each identified volume to obtain the global unique identifier (GUID) associated with the volume. In response to the command, the volume transmits to interceptor appliance 890 a message specifying its global unique identifier. Based on the GUIDs received in this manner, interceptor process 810 determines how many unique volumes are present and whether any of the identified volumes are redundant. The implementation of the global unique identifier for each volume may vary based on the manufacturer of the storage system. In some embodiments, non-standard commands may be required to retrieve the information which constitutes the GUID.

Using the methods described herein, interceptor appliance 890 identifies an initiator WWPN that is zoned to a selected target port of storage system 180, and identifies one or more volumes within storage system 180 that the initiator WWPN may access. This method may be used to identify multiple WWPNs associated with a selected server (or host entity). Interceptor appliance 180 may then identifies all volumes within storage system 180 that the WWPNs may access. Interceptor appliance 890 may therefore identify all volumes to which the server or host entity has access.

The systems and methods described herein advantageously allow the insertion of interceptor appliance 890 in the data path between FC switch 225 and storage system 180 such that all I/O commands may be intercepted transparently. The systems and methods described herein further allow insertion of the interceptor appliance 890 transparently, without interrupting the operation of storage system 180 or of the network.

Provision of Data Management Services

In accordance with an embodiment, interceptor appliance 890 provides one or more data management services with respect to data stored in storage system 180. Referring to FIG. 8, interceptor appliance 890 comprises a data management service 848 which includes functionality to provide one or more data management services. For example, data management service 848 may include functionality to copy data, to perform a snapshot of a data image, to back up data, to replicate data, to perform data migration from one storage device or system to another, etc. Data management service 848 may comprise user interface functions. For example, the storage volumes and host entities identified by interceptor appliance 890 using the methods described herein may be presented to a user by use of a user interface to facilitate selection by the user of one or more volumes and one or more services that the user wishes to have performed with respect to the selected volumes.

In one embodiment, after identifying one or more volumes to which a particular server or host entity has access, in the manner described above, interceptor appliance 890 may use this information to provide one or more data management services. FIG. 11 shows another embodiment of communication system 100 that may be used to provide data management services. In the embodiment of FIG. 11, communication system 100 also comprises a backup storage system 1140 linked to network 115. In an illustrative embodiment, interceptor appliance 890 includes functionality to copy one or more volumes to which a particular host entity (in this example, server 135-A) is granted access. Accordingly, interceptor appliance 890 identifies a volume in storage system 180 to which the host entity has access, and copies the volume to backup storage system 1140.

To ensure a complete and accurate copy in the event that new data is written to the volume by the host entity while data is being copied, interceptor appliance 890 records the locations of any data that is written to the volume during the copy procedure. In this manner, interceptor appliance 890 keeps track of new data written to the volume. After a first pass is completed, interceptor appliance 890 consults the record indicating the locations of new data and copies the new data in a subsequent pass. Additional passes may be performed as well.

FIG. 12 is a flowchart of a method of providing data management services in accordance with an embodiment. At step 1210, an identifier of an initiator port of a host entity connected to a switch is determined by a device located in a path between a switch port of the switch and a target port of a storage system. In the manner described above, interceptor process 810 of interceptor appliance 890 identifies the initiator WWPN of initiator port I-1 of the host entity (server 135-A). In the illustrative embodiment, the WWPN of initiator port I-1 is WWPN-1.

At step 1220, a storage volume in the storage system to which the initiator port has access is identified, based on the identifier. In the illustrative embodiment, interceptor process 810 determines that WWPN-1 has access to volume-1 maintained in storage system 180, in the manner described above.

After a volume in storage system 180 is identified, with detailed and precise information specifying one or more initiator WWPNs of the host entity, interceptor appliance 890 may intercept I/O commands and determine the origin of each I/O command received. This allows data management service 848 (of interceptor appliance 890) to perform one or more selected actions with respect to each I/O command based on the origin of the I/O command.

At step 1230, a data management service is provided with respect to the identified storage volume. Referring to FIG. 8, data management service 848 (of interceptor appliance 890) accesses volume-1 and copies the data in volume-1 to another volume. In the illustrative embodiment of FIG. 11, data management service 848 copies data in volume-1 to a volume in backup storage system 1140.

Before copying data, data management service 848 instructs interceptor process 810 to intercept all data write commands. Data management service 848 then commences copying data in the volume from the beginning to the end in a sequential manner. While the copying procedure is being performed, new data may be written to portions of the volume that have already been copied. To ensure an up-to-date copy, data management service 848 records the locations of all new data that is written to the volume. After a first pass is completed, data management service 848 copies the locations where new data has been written, in a subsequent pass. Additional passes may be performed if necessary.

In other embodiments, data managements service 848 may provide other types of services, such as performing a snapshot of a data image, replicating data, performing data migration from one storage device or system to another, etc. When other functions are performed, interceptor process 810 intercepts I/O commands as necessary to enable such functions to be performed. In another embodiment, data management service 848 may monitor I/O commands sent to and from a selected volume maintained in storage system 180, and may generate statistics relating to the I/O commands. In another embodiment, data management service 848 may monitor traffic to and from a selected storage volume and call a predetermined function to perform a specified action, if a predetermined condition is detected. For example, data management service 848 may notify an administrator if a specified initiator port writes data to the selected volume.

While the embodiments described herein are described in the context of a Fibre channel-based SAN, the methods and systems described herein are not limited to use within a Fibre channel-based SAN. In other embodiments, methods and systems described herein may be used in connection with other types of communication systems and networks. For example, methods and systems described herein may be used in a communication system using iSCSI protocols.

In various embodiments, the method steps described herein, including the method steps described in FIGS. 10 and/or 12, may be performed in an order different from the particular order described or shown. In other embodiments, other steps may be provided, or steps may be eliminated, from the described methods.

Systems, apparatus, and methods described herein may be implemented using digital circuitry, or using one or more computers using well-known computer processors, memory units, storage devices, computer software, and other components. Typically, a computer includes a processor for executing instructions and one or more memories for storing instructions and data. A computer may also include, or be coupled to, one or more mass storage devices, such as one or more magnetic disks, internal hard disks and removable disks, magneto-optical disks, optical disks, etc.

Systems, apparatus, and methods described herein may be implemented using computers operating in a client-server relationship. Typically, in such a system, the client computers are located remotely from the server computer and interact via a network. The client-server relationship may be defined and controlled by computer programs running on the respective client and server computers.

Systems, apparatus, and methods described herein may be used within a network-based cloud computing system. In such a network-based cloud computing system, a server or another processor that is connected to a network communicates with one or more client computers via a network. A client computer may communicate with the server via a network browser application residing and operating on the client computer, for example. A client computer may store data on the server and access the data via the network. A client computer may transmit requests for data, or requests for online services, to the server via the network. The server may perform requested services and provide data to the client computer(s). The server may also transmit data adapted to cause a client computer to perform a specified function, e.g., to perform a calculation, to display specified data on a screen, etc.

Systems, apparatus, and methods described herein may be implemented using a computer program product tangibly embodied in an information carrier, e.g., in a non-transitory machine-readable storage device, for execution by a programmable processor; and the method steps described herein, including one or more of the steps of FIGS. 10 and/or 12, may be implemented using one or more computer programs that are executable by such a processor. A computer program is a set of computer program instructions that can be used, directly or indirectly, in a computer to perform a certain activity or bring about a certain result. A computer program can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

A high-level block diagram of an exemplary computer that may be used to implement systems, apparatus and methods described herein is illustrated in FIG. 13. Computer 1300 includes a processor 1301 operatively coupled to a data storage device 1302 and a memory 1303. Processor 1301 controls the overall operation of computer 1300 by executing computer program instructions that define such operations. The computer program instructions may be stored in data storage device 1302, or other computer readable medium, and loaded into memory 1303 when execution of the computer program instructions is desired. Thus, the method steps of FIG. 10 can be defined by the computer program instructions stored in memory 1303 and/or data storage device 1302 and controlled by the processor 1301 executing the computer program instructions. For example, the computer program instructions can be implemented as computer executable code programmed by one skilled in the art to perform an algorithm defined by the method steps of FIGS. 10 and/or 12. Accordingly, by executing the computer program instructions, the processor 1301 executes an algorithm defined by the method steps of FIGS. 10 and/or 12. Computer 1300 also includes one or more network interfaces 1304 for communicating with other devices via a network. Computer 1300 also includes one or more input/output devices 1305 that enable user interaction with computer 1300 (e.g., display, keyboard, mouse, speakers, buttons, etc.).

Processor 1301 may include both general and special purpose microprocessors, and may be the sole processor or one of multiple processors of computer 1300. Processor 1301 may include one or more central processing units (CPUs), for example. Processor 1301, data storage device 1302, and/or memory 1303 may include, be supplemented by, or incorporated in, one or more application-specific integrated circuits (ASICs) and/or one or more field programmable gate arrays (FPGAs).

Data storage device 1302 and memory 1303 each include a tangible non-transitory computer readable storage medium. Data storage device 1302, and memory 1303, may each include high-speed random access memory, such as dynamic random access memory (DRAM), static random access memory (SRAM), double data rate synchronous dynamic random access memory (DDR RAM), or other random access solid state memory devices, and may include non-volatile memory, such as one or more magnetic disk storage devices such as internal hard disks and removable disks, magneto-optical disk storage devices, optical disk storage devices, flash memory devices, semiconductor memory devices, such as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), digital versatile disc read-only memory (DVD-ROM) disks, or other non-volatile solid state storage devices.

Input/output devices 1305 may include peripherals, such as a printer, scanner, display screen, etc. For example, input/output devices 1305 may include a display device such as a cathode ray tube (CRT) or liquid crystal display (LCD) monitor for displaying information to the user, a keyboard, and a pointing device such as a mouse or a trackball by which the user can provide input to computer 1300.

Any or all of the systems and apparatus discussed herein, including client 160, server 135, Fibre channel switch 225, storage system 180, and interceptor appliance 890, and components thereof, including service manager 325, memory 375, storage manager 410, memory 475, storage 468, switch manager 525, memory 575, interceptor process 810, memory 815, data management service 848 and all ports within any of these apparatus or components, may be implemented using a computer such as computer 1300.

One skilled in the art will recognize that an implementation of an actual computer or computer system may have other structures and may contain other components as well, and that FIG. 13 is a high level representation of some of the components of such a computer for illustrative purposes.

The foregoing Detailed Description is to be understood as being in every respect illustrative and exemplary, but not restrictive, and the scope of the invention disclosed herein is not to be determined from the Detailed Description, but rather from the claims as interpreted according to the full breadth permitted by the patent laws. It is to be understood that the embodiments shown and described herein are only illustrative of the principles of the present invention and that various modifications may be implemented by those skilled in the art without departing from the scope and spirit of the invention. Those skilled in the art could implement various other feature combinations without departing from the scope and spirit of the invention. 

The invention claimed is:
 1. A non-transitory computer readable medium having program instructions stored thereon, that, in response to execution by a computing device located in a path between a switch port of a switch and a target port of a storage system, cause the computing device to perform operations comprising: identifying a target world wide port name of the target port of the storage system; registering, in a first registration procedure, a first port of the computing device with the switch based on the target world wide port name; receiving, in a second registration procedure, registration information comprising first information relating to an initiator port of a server that is associated with the target port and second information specifying a particular switch port to which the initiator port is connected; determining an initiator world wide port name of the initiator port of the server, based on the registration information; and identifying a storage volume in the storage system that is associated with the initiator port, based on the initiator world wide port name of the initiator port.
 2. The non-transitory computer readable medium of claim 1, further comprising program instructions, which, in response to execution by the computing device, cause the computing device to perform operations comprising: assigning the target world wide port name to the first port of the computing device.
 3. The non-transitory computer readable medium of claim 1, wherein the second registration procedure comprises registration by the initiator port with the computing device via the first port.
 4. The non-transitory computer readable medium of claim 3, further comprising program instructions, which, in response to execution by the computing device, cause the computing device to perform operations comprising: receiving, in the second registration procedure, a switch port identifier associated with an initiator port of a server that is zoned to the target port.
 5. The non-transitory computer readable medium of claim 1, further comprising program instructions, which, in response to execution by the computing device, cause the computing device to perform operations comprising: accessing a Simple Name Server table that identifies, for each of one or more ports of the switch, a corresponding world wide port name.
 6. The non-transitory computer readable medium of claim 1, further comprising program instructions, which, in response to execution by the computing device, cause the computing device to perform operations comprising: transmitting, to the storage system, a REPORT LUN command including the initiator world wide port name; and receiving, from the storage system, in response to the REPORT LUN command, information identifying the storage volume to which the initiator world wide port name has access.
 7. The non-transitory computer readable medium of claim 6, further comprising program instructions, which, in response to execution by the computing device, cause the computing device to perform operations comprising: transmitting, to the storage system, a SCSI inquiry relating to the storage volume to which the initiator world wide port name has access; receiving, in response to the SCSI inquiry, information indicating a global unique identifier of the storage volume; and determining whether two storage volumes associated with the initiator world wide port name are identical based on the global unique identifier.
 8. The non-transitory computer readable medium of claim 1, further comprising program instructions, which, in response to execution by the computing device, cause the computing device to perform operations comprising: registering, by the computing device, in the first registration procedure, the first port of the computing device with the switch based on the target world wide port name and on a second world wide port name uniquely associated with the first port of the computing device.
 9. The non-transitory computer readable medium of claim 1, further comprising program instructions, which, in response to execution by the computing device, cause the computing device to perform operations comprising: adding the initiator world wide port name of the initiator port of the server to an interceptor port of the computing device; adding a second initiator world wide port name of a second initiator port of the server to the interceptor port of the computing device; transmitting, by the interceptor port of the computing device, to the storage system, one or more commands specifying the initiator world wide port name of the initiator port of the server and the second initiator world wide port name of the second initiator port of the server; identifying, by the computing device, a first storage volume in the storage system that is associated with the initiator port, based on the initiator world wide port name of the initiator port; and identifying, by the computing device, a second storage volume in the storage system that is associated with the second initiator port, based on the second initiator world wide port name of the second initiator port.
 10. An apparatus comprising: means for identifying a target world wide port name of a target port of a storage system; means for registering, in a first registration procedure, a first port of a computing device with a switch based on the target world wide port name; means for receiving, in a second registration procedure, registration information comprising first information relating to an initiator port of a server that is associated with the target port and second information specifying a particular switch port to which the initiator port is connected; means for determining an initiator world wide port name of the initiator port of the server, based on the registration information; and means for identifying a storage volume in the storage system that is associated with the initiator port, based on the initiator world wide port name of the initiator port.
 11. The apparatus of claim 10, further comprising: means for assigning the target world wide port name to the first port of the computing device.
 12. The apparatus of claim 10, wherein the second registration procedure comprises registration by the initiator port with the computing device via the first port.
 13. The apparatus of claim 10, further comprising: means for receiving, in the second registration procedure, a switch port identifier associated with an initiator port of a server that is zoned to the target port.
 14. The apparatus of claim 10, further comprising: means for accessing a Simple Name Server table that identifies, for each of one or more ports of the switch, a corresponding world wide port name.
 15. The apparatus of claim 10, further comprising: means for transmitting, to the storage system, a REPORT LUN command including the initiator world wide port name; and means for receiving, from the storage system, in response to the REPORT LUN command, information identifying the storage volume to which the initiator world wide port name has access.
 16. The apparatus of claim 15, further comprising: means for transmitting, to the storage system, a SCSI inquiry relating to the storage volume to which the initiator world wide port name has access; means for receiving, in response to the SCSI inquiry, information indicating a global unique identifier of the storage volume; and means for determining whether two storage volumes associated with the initiator world wide port name are identical based on the global unique identifier.
 17. The apparatus of claim 10, further comprising: means for registering, in the first registration procedure, the first port of the computing device with the switch based on the target world wide port name and on a second world wide port name uniquely associated with the first port of the computing device.
 18. The apparatus of claim 10, further comprising: means for adding the initiator world wide port name of the initiator port of the server to an interceptor port of the computing device; means for adding a second initiator world wide port name of a second initiator port of the server to the interceptor port of the computing device; means for transmitting, to the storage system, one or more commands specifying the initiator world wide port name of the initiator port of the server and the second initiator world wide port name of the second initiator port of the server; means for identifying a first storage volume in the storage system that is associated with the initiator port, based on the initiator world wide port name of the initiator port; and means for identifying a second storage volume in the storage system that is associated with the second initiator port, based on the second initiator world wide port name of the second initiator port. 